Agricultural land used for....? Obvious surely?

Well yes even to me but only up to a point!

My "up to a point" suppositions are that it is not possible to be built on (possibly ever), can be used for any legal crop, keep domestic animals on or just have as a field.

Beyond that is the point of my question. For example, could I put up wooden buildings such as hen house, pig shelter, stables, barn etc all having agricultural purpose? Could I put up a greenhouse, have a duck or fish pond? Could I plant a forest of trees thereby creating woodland - is that different to agricultural land? Is there a difference to growing / rearing things for my personal use as compared to using for business purposes?

As ever, your insight would be much appreciated.

Agree with Vic and several neighbours who are all French and one a council member have done the same. Just do it.

On my "agricultural" land I've created a very large veggy patch with an 8 x 5 m poly tunnel & fruit cages. I've planted a largish orchard & put a large outside chicken coop in it. The mayor & other commune peoples come here for drinks etc. & nobody has said anything other than the French equivalent of " Blimey, you've changed this wreck of a house & land for the better." Nobody seems to care what I do with it as long as I don't build another house this space!!!